Absorbent bandage

ABSTRACT

An absorbent bandage or sanitary napkin suitable for use as either a catamenial or an incontinent device adapted to conform more effectively to the shape of the body in the area of the female genitalia whether the wearer is in a standing, sitting or lying position, said napkin being so constructed as to assume an upwardly concave conformation in both the transverse and the longitudinal directions when worn. The absorbent pad of a preferred embodiment of a sanitary napkin of the present invention is comprised of a basically hydrophobic, non-woven, needle-punched polyester two sheet of relatively low density in contiguous association with one or more absorbent core layers of basically hydrophilic bleached wood pulp fibers airlaid and compressed into a continuous web of relatively high density. The interface thus formed between the top sheet and the absorbent core provides a gradient of diminishing capillary size between the top sheet which has a relatively large pore structure and the absorbent core which has a relatively small pore structure, which gradient promotes rapid transmission of body fluids into the absorbent core material, thereby minimizing lateral spreading of body fluids deposited on the top sheet. This permits more effective utilization of the absorptive capacity of the absorbent core material, and prevents migration of body fluids absorbed by the absorbent core material back through the surface of the topsheet, thereby retaining absorbed body fluids within an envelope formed by the waterproof backing sheet adjacent its lowermost surface and the top sheet which overwraps its uppermost surface and its edge portions.

United States Patent [191 Duncan et al.

[ Mar. 18, 1975 ABSORBENT BANDAGE [75] Inventors: Robert C. Duncan,Wyoming; Grace L. Smith, Cincinnati, both of Ohio [73] Assignee: TheProcter & Gamble Company, Cincinnati, Ohio 221 Filed: Mar. 22, 1973 21Appl. No.: 343,774

[52] U.S. Cl. 128/290 [51] Int. Cl. A6lf 13/16 [58] Field of Search128/290 R, 290 W, 290 P,

[56] References Cited UNITED STATES PATENTS 2,964,039 12/1960 Johnson,Jr. et a1 128/290 R 3,575,174 4/1971 Mogor 128/290 R 3,621,847 11/1971Roberson 128/290 R 3,736,931 6/1973 Glassman 128/290 R PrimaryExaminerLucie H. Laudenslager Attorney, Agent, or Firm-E. Kelly Linman;Frederick H. Braun; John V. Gorman [5 7] ABSTRACT An absorbent bandageor sanitary napkin suitable for use as either a catamenial or anincontinent device adapted to conform more effectively to the shape ofthe body in the area of the female genitalia whether the wearer is in astanding, sitting or lying position, said napkin being so constructed asto assume an upwardly concave conformation in both the transverse andthe longitudinal directions when worn. The absorbent pad of a preferredembodiment of a sanitary napkin of the present invention is comprised ofa basically hydrophobic, non-woven, needle-punched polyester two sheetof relatively low density in contiguous association with one or moreabsorbent core layers of basically hydrophilic bleached wood pulp fibersairlaid and compressed into a continuous web of relatively high density.The interface thus formed between the top sheet and the absorbent coreprovides a gradient of diminishing capillary size between the top sheetwhich has a relatively large pore structure and the absorbent core whichhas a relatively small pore structure, which gradient promotes rapidtransmission of body fluids into the absorbent core material, therebyminimizing lateral spreading of body fluids deposited on the top sheet.This permits more effective utilization of the absorptive capacity ofthe absorbent core material, and prevents migration of body fluidsabsorbed by the absorbent core material back through the surface of thetopsheet, thereby retaining absorbed body fluids within an envelopeformed by the waterproof backing sheet adjacent its lowermost surfaceand the top sheet which overwraps its uppermost surface and its edgeportions.

18 Claims, 6 Drawing Figures PATEN MAR 1 8 i975 SHEET 1 UF 2 Fig. 3

ABSORBENT BANDAGE FIELD OF THE INVENTION This invention relates toabsorbent bandages, particularly sanitary napkins, and more particularlyto sanitary napkins or other structures suitable for use either as acatamenial or an incontinent device. In a preferred embodiment, thenapkin will assume an upwardly concave conformation when worn. Inanother preferred embodiment, the napkin includes a forward extension ofthe absorbent pad which is unrestrained and is hence free to bendrelative to the main body of the absorbent pad to form a seal againstthe frontal portions of the body. In addition, this invention hasparticular relation to absorbent bandages, particularly sanitarynapkins, wherein the absorbent core is comprised preferably of amultiplicity of layers of relatively dense, basically hydrophilic,compressed airfelt in contiguous association with a waterproof backingsheet on its lowermost surface and overwrapped on its uppermost surfaceand edge portions by a top sheet of basically hydrophobic, non-woven,relatively low density material to produce a favorable density gradientbetween the top sheet and the absorbent core material. This in turnpromotes rapid transmission of menses or other discharged body exudateinto the absorbent core material, minimizes lateral spreading of suchbody fluids on the topsheet, utilizes more effectively the absorptivecapacity of the absorbent core material, and retains body fluidsabsorbed by the absorbent core material within an envelope formed by thewaterproof backing sheet and the top sheet.

BACKGROUND OF THE INVENTION Absorbent pads, and especially sanitarynapkins, have been made in a variety of shapes and have incorporatednumerous structural features in attempts to provide an article of suchnature which fulfills its absorbing function and which is alsocomfortable and non-chafing when worn.

Sanitary napkins which are in common use generally have the shape of arectangular parallelepiped which is enclosed by a fluid permeable coverwhich is elongated at both ends of the napkin to provide attachment tabsintended to be attached to the clasps of a sanitary belt at the frontand rear of the wearer. Tensional forces induced uniformly along theleading edge of the absorbent core by attachment of such a napkin to asanitary belt bend'the ends of the sanitary napkin upwardly in thelongitudinal direction, while lateral compressional forces inconjunction with the uniformly induced tensional forces, particularly inthe region rearward of the vulva between the buttocks, bend the sides ofthe napkin downwardly so that it forms a downwardly concave or aninverted U-shape in order to conform to the contours of the female pubicarch. Thus, body fluids deposited on the upper surface of the downwardlyconcave transverse section have a natural tendency, due to the shape ofthe structure, to run downwardly toward the lateral edges of the pad,thereby promoting run-off and soiling of undergarments. Such externalforces applied to the napkin also tend to produce irregular surfaces inthe napkin, particularly along the uppermost portions of its lateraledges, which generally take the form of troughs, folds, trianglesridges, flutes, etc., thereby preventing intimate contact between thenapkin and the body of the wearer in the area of the vulva where snugfit is most important.

Such downwardly concave curvature also promotes slippage of such anapkin and smearing. Slippage is relative movement between the napkinand the trunk of the body of the wearer; smearing is the soiling ofparts of the body of the wearer adjacent the labia majora, usually as aresult of slippage.

Since most prior art sanitary napkins have absorbent pads which are ofuniform cross section at any point along their longitudinal axis,greater tensional forces are required to cause such a pad to assume anupwardly concave configuration in the longitudinal direction to conformto the female anatomy, thereby producing greater discomfort to thewearer. This is primarily due to deformation of the external femaleorgans coming in contact with the uppermost surface of the pad. Suchrectangular style napkins are also uncomfortable to the wearer from thestandpoint of chafing, due to the fact that the lateral edges of thenapkin contact the inner portions of the thighs at a point whereconsiderable movement occurs relative to the trunk of the body, andhence movement also occurs relative to the lateral edge portions ofthenapkin. Movement of the thighs relative to the lateral edges of thenapkin causes irritating frictional forces to be exerted against theinner portions of the thighs, and at the same time tends to promoterunoff from the lateral edge portions of the napkin due to the fact thata seal is not maintained along such lateral edge portions of the napkinin the area of the body where body fluids are usually deposited.

In an attempt to eliminate the above problems, sanitary napkins havebeen made from conventional overwrap and core materials with rearwardportions of reduced size to'conform more nearly to the configuration ofthe female anatomy in the area of the buttocks. Such a reduction in sizehas usually been accomplished by reducing the amount of absorbentmaterial contained in the rearward end of the napkin either by cuttingaway portions of the napkin along the sides of the rearward portion orby forming the napkin initially with less absorbent material in therearward portion. Such procedures have generally been satisfactory fromthe standpoint of improved comfort. However, considerable sacriflce ismade with respect to providing an effective absorbing medium for theoverall performance of such a sanitary napkin due to the fact that verypoor fluid transfer characteristics are inherent in prior art sanitarynapkins, regardless of shape or size. This is due to the fact that thefluid pervious overwrap material used in such napkins is typically moredense than the core material, thus providing a gradient of increasingcapillary size in the direction of the core material which tends toinhibit fluid transfer from the top sheet to the absorbent corematerial.

An alternative approach to forming a sanitary napkin with a reduced sizein its'rearward portion has been to provide a sanitary napkin having apreformed arcuate configuration in the longitudinal direction, therebyeliminating or at least greatly reducing the tensional forces requiredto bend an initially flat sanitary napkin into the desired in useconfiguration. Preforming a sanitary napkin into an arcuateconfiguration eliminates the transverse ridges and troughs which arenormally formed in the uppermost surface when a normally flat sanitarynapkin is subjected to tension to force it to conform to the femaleanatomy by attachment to a sanitary belt. Elimination of these ridgesand troughs is important because they encourage the flow of body fluidsdeposited on the top sheet to the sides of the napkin. This results inthe soiling of undergarments and consequent in-use failure of the napkinsubstantially before the full utilization of its absorptive capacity.However, for a sanitary napkin to obtain a preformed, arcuateconfiguration, it has usually been necessary to build in stabilizingforces within the napkin, itself. This is normally done by providingshrinkable elements strategically placed within the sanitary napkin orby having thermoplastic or thermosetting moldable elements strategicallydistributed throughout the napkin which, upon activation by heat orchemical treatment, are effective to draw the sanitary napkin into thedesired arcuate configuration, or which, by placement into suitablemolding forms, are effective to mold the sanitary napkin into itsdesired configuration. Such processes, however, are usually expensive,and sometimes have the effect of substantially reducing the effectiveabsorption characteristics of the absorbent core, particularly wheresuch napkins employ water insoluble binders. Lack of absorptive capacityreduces potential wearing time and increases the possibility of in-usefailure. In addition, such products are usually stiff and, therefore,must be shaped precisely to fit the body to be comfortable.

In absorbent bandages, and particularly in sanitary napkins, it isextremely desirable that the construction be such that any dischargedbody fluids which strike the surface thereof be carried to the interiorof the pad as rapidly as possible to be distributed evenly throughoutthe interior absorbent portion and retained therein. If this isaccomplished effectively, excessive spreading of the fluid on thesurface and eventually over the edges of the pad is avoided.

In prior art sanitary napkins, the absorbent core material is usuallyoverwrapped by an outer pervious covering which may be comprised fromgauze, non-woven threads, non-woven fabric, or the like. Because theabsorbent core material in prior art napkins is usually of considerablylower density than the top sheet material, fluid deposited on the topsheet will not be rapidly transmitted into the core, but rather willtend to spread laterally on the surface of the top sheet, therebyproducing an objectionable appearance and feel, causing discomfort andpromoting run-off and soiling of undergarments. In addition, fluidabsorbed in the core material will tend to migrate back to the surfaceof the top sheet due to the unfavorable density gradient existingbetween the top sheet and the absorbent core material, thereby causingthe top sheet to feel moist.

OBJECTS OF THE INVENTION favorable capillary size and liquid contactangle gradients which exist between the top sheet and the absorbent corematerial, regardless of whether the absorbent core material is in a dryor a moist state.

It is'a further object of the present invention to provide a sanitarynapkin which is more comfortable to wear due not only to improvements insoftness of the relatively dense absorbent core material, but also to anoverall reduction in size, particularly toward the rearward portion ofthe absorbent pad, and to the tendency of the absorbent pad to assume anupwardly concave or U configuration in both the transverse and thelongitudinal directions when worn.

It is a further object of the present invention to provide a forwardextension of the absorbent pad which is capable of bending relative tothe main body of the absorbent pad so as to better conform to thefrontal portions of the female body, and thereby form a dam over whichbody exudate cannot flow.

It is a further object of the present invention to preventstrike-through of body exudate from the lowermost side of a sanitarynapkin of the present invention by providing a waterproof backing sheetessentially coextensive with the lowermost layer of absorbent corematerial.

SUMMARY OF THE INVENTION According to the present invention, anabsorbent bandage is provided, preferably in the form of a sanitarynapkin, which utilizes more effectively the available absorbent corematerial provided in the napkin by providing a favorable densitygradient between the top sheet and the absorbent core material. This inturn results in corresponding gradients of capillary size and liquidcontact angle which cause exuded body fluids to preferentially pass toand accumulate in the absorbent core of the napkin. A non-wovenhydrophobic top sheet material having a density range of fromapproximately 0.03 to approximately 0.13 gm. per cubic centimeter asmeasured under a load of 50 gm. per square inch and a hydrophiliccompressed absorbent core having a density range of from approximately0.15 to approximately 0.30 gm. per cubic centimeter as measured under aload of 50 gm. per square inch is contemplated in the present invention.Thus, fluid deposited on the surface of the basically hydrophobic topsheet will transfer at a considerably more rapid rate to the more densecompressed absorbent core than is the case with prior art sanitarynapkins. Since the absorbent core in a preferred embodiment is basicallyhydrophilic, it will absorb the moisture transmitted from the top sheet,while the top sheet remains relatively dry.

In one preferred embodiment of the present invention, a sanitary napkinis provided having reduced size, particularly toward the rearwardportion thereof, and which, when worn, assumes an upwardly concave orU-configuration in both the transverse and the longitudinal directions.This avoids deformation of the natural contours of the body portionsadjacent thereto. The lateral edges portions of the absorbent pad of asanitary napkin of the present invention are accommodated in the vaultsformed by the jointure of each thigh and the adjacent labium majora,while the central portion of the absorbent pad moves downwardly.

The absorbent pad, in one preferred embodiment, is constructed so thatit readily assumes an upwardly concave configuration in the transversedirection. This is achieved by providing a longitudinal depression alongthe central portion of the top surface of the absorbent pad which tendsto bias the pad into an upwardly concave or U" shape. Additionally, atransverse slit is provided intermediate the lateral edges of the bottomsheet material at a point in vertical alignment with the forwardmostedge of the main body of the absorbent pad, i.e., that portion of thepad not including the forwardmost extension thereof, thereby relievingthe central portion of the absorbent pad of stress when worn, andconcentrating the tensile stress induced by application of the napkin toa sanitary belt along the lateral edge portions of the absorbent pad.

In another embodiment, a structure is provided which prevents the flowof discharged fluids over the leading edge of the napkin whilesimultaneously providing better conformance of the frontal portions ofthe napkin to the female body. This is provided by structuring thelowermost layer of absorbent core material and the waterproof backingsheet with forward projections extending beyond the main body of theabsorbent pad. The aforementioned projections are overwrapped only bytop sheet material. The front extension thus formed is free to bendrelative to the main body of the absorbent pad, and allows the napkin toconform more readily to individual body shape, thereby effectivelyforming a dam against the body.

The unique features described above when combined in a preferredembodiment of the present invention result in a sanitary napkin which ismore comfortable to the wearer both in terms of fit and dryness, whichgives the wearer a greater feeling of security against smearing, run-offand strike-through, and which can be worn for longer periods of time dueto more effective utilization of the absorbent core material.

BRIEF DESCRIPTION OF THE DRAWINGS While the specification concludes withclaims particularly pointing out and distinctly claiming the subjectmatter which is regarded as the present invention, it is believed thatthe invention will be better understood from the following descriptiontaken in connection with the accompanying drawings, in which:

FIG. 1 is an exploded perspective view of a sanitary napkin which is onepreferred embodiment of the present invention, wherein the individualcomponents are depicted in their unassembled relation;

FIG. 2 is a perspective view showing partial assembly of the componentsillustrated in FIG. 1, and further depicting the manner in which the topsheet is folded about the other assembled components;

FIG. 3 is a perspective view of one preferred embodiment of a completelyassembled sanitary napkin made in accordance with the present inventionprior to use by a consumer;

FIG. 4 is a perspective view of one preferred embodiment of a completelyassembled sanitary napkin of the present invention shown in its in-useconfiguration when attached to the clasps of a sanitary belt or holder;

FIG. 5 is an enlarged transverse sectional view of one preferredembodiment of a sanitary napkin of the present invention when placed inuse by a consumer, such sectional view being taken at approximately thesame point as section line 66 in FIG. 3; and

FIG. 6 is an enlarged transverse sectional view of one preferredembodiment of a completely assembled sanitary napkin of the presentinvention taken along section line 66 in FIG. 3, showing the napkin inits configuration prior to use.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, there isshown an exploded view of the individual components of one embodiment ofthe absorbent bandage of the present invention. It will become apparentas the description proceeds that a sanitary napkin is a most preferredembodiment, although it will be understood that other similar equivalentarticles, e.g., disposable diapers, incontinent pads and the like, arewithin the broad scope of the invention. The components in FIG. I areshown in the same relative position in which they are ultimatelyassembled.

The preferred construction of a sanitary napkin includes a top sheet 1which comes in contact with the users skin. The top sheet 1 ispreferably a non-woven material. Very good results have been obtained inusing a non-woven, needle-punched polyester material having a density inthe range of from about 0.03 to about 0.13 gm. per cubic centimeter asmeasured under a load of 50 gm. per square inch, preferably betweenapproximately 0.03 and 0.08 gm. per cubic centimeter. One such materialwhich has proven highly satisfactory in this service is a non-woven, 3denier, 2% oz. per square yard, needle-punched polyester fabric having acaliper of approximately 0.09 in. and a density of approximately 0.03gm. per cubic centimeter, such as is available from Troy Mills, Troy,New Hampshire. While the above mentioned needle-punched polyestermaterial is preferred, the invention can also be practiced withsimilarly good results by the use of similar or equivalent materialssuch as: a non-woven, 6 denier, needle-punched polyester fabric having acaliper of approximately 0.11 in. and a density of about 0.04 gm. percubic centimeter, such as Troy Mills code No. 3001-007500 also availablefrom Troy Mills, Troy, New Hampshire; a non-woven, 6 denier,needlepunched Type 209 polyester fabric having a caliper of either 0.08in. or 0.09 in. and a density of about 0.04 gm. per cubic centimeter,such as Stearns & Foster grade 0 or grade K material available from TheStearns & Foster Company, Lockland, Ohio; or a resinbonded polyesterfabric having a caliper of approximately 0.014 in. and a density ofabout 0.13 gm. per cubic centimeter, such as Stearns & Foster grade No.2552 available from The Stearns & Foster Company, Lockland, Ohio. Thetop sheet material exhibits hydrophobic properties in that it does notreadily absorb moisture which comes in contact with it, but rathertransmits it to the hydrophilic core layers 2 and 3 which absorb anddistribute the moisture. The top sheet 1 has front and rear extensions 6and 13 and lateral extensions 7, 8, 9, 10, 11 and 12. A detaileddescription of how these extensions are utilized to join the top sheetto the other components of the sanitary napkin will be given following amore complete description of the individual components.

The absorbent core is preferably comprised of a multiplicity of layersof airfelt or equivalent materials, e.g., cellulose wadding, rayon mat,etc. Preferably three layers of airfelt are utilized, ordinarily twoupper layers of basically hydrophilic compressed airfelt 2, and alowermost layer 3, the latter being of similar configuration to thelayers 2 except for the addition of a trapezoidal extension 3a at itsleading edge, i.e., its forward portion 3a as shown in FIGS. 1 and 2. Bycompressing the airfelt in this particular application, the density ofthe core material can be increased from approximately 0.04 gm. per cubiccentimeter as measured under a load of 50 gm. per square inch tosomething in the range of approximately 0.15 to approximately 0.30 gm.per cubic centimeter as measured under the same load, preferably betweenapproximately 0.22 and 0.26 gm. per cubic centimeter, thus producing avery favorable density gradient with respect to the low density topsheet 1.

Immediately following dry compression, the densified airfelt in apreferred embodiment may be subjected to any one of a number ofprocesses designed to provide acceptable lateral softness in thefinished product, e.g., mechanical microcreping carried out betweendifferentially loaded rubber belts and/or a differentially loaded rubberbelt and a hard surface. Such a process imparts softness and complianceto the airfelt, which would not otherwise result if only dry compressionwere utilized. A test designed to measure the flexual rigidity orstiffness of paperboard, which utilizes a Taber V- Stiffness Tester,Model 150 B, as manufactured by the Taber Instrument Corporation ofNorth Tonawanda, New York, can also be used to measure the flexuralrigidity or stiffness of the absorbent core material, in this casecompressed airfelt, by determining the bending moment ingram-centimeters necessary to defleet the free end ofa 3.81 cm. (1.5in.) wide vertically clamped specimen of compressed airfelt having anoverall length of 6.99 cm. (2.75 in.) from its center line when the loadis applied 5 centimeters away from the clamp. Compressed airfelt havinga caliper of between 0.127 and 0.152 cm. (0.05 and 0.06 in.) such as isused in the absorbent core of a preferred embodiment of the presentinvention typically exhibits a softness range between 1.2 and 8.7gram-centimeters, whereas compressed airfelt of equivalent caliper whichhas not been subjected to any type of process to impart softness afterdry compression typically exhibits a softness range between 10 and 18gram-centimeters. The use of compressed airfelt in this particularapplication allows the pad size to be kept to a minimum, i.e, thecaliper of a layer of uncompressed airfelt is typically reduced fromapproximately 0.35 in. as measured under a load of 50 gm. per squareinch to approximately 0.09 in. to 0.10 in. under the same load after drycompression and trimming to the preferred size, thereby permittingmaximum use of absorbent material. ln addition, pre-compressing theairfelt prior to assembly of a napkin of the present invention providesa mechanism by which the airfelt is able to absorb greater quantities offluid, since the airfelt will tend to expand back toward its originaluncompressed state when it absorbs liquid. While in a preferredstructure the absorbent core comprises three layers, e.g., the layers 2,2 and 3, it will be understood that it is possible to make the absorbentcore from any number of layers, i.e., one or more layers, depending uponthe desired construction of the finished product.

The waterproof backing sheet 4 can be of any pliable waterproofmaterial. One such material which has proven satisfactory in thisservice is embossed hard polyethylene having an embossed caliper ofapproximately 2.3 mils, such as is available from Visqueen Division ofEthyl Corporation, Terre Haute, Indiana. The waterproof backing sheet 4is essentially coextensive with the lowermost layer of absorbent corematerial 3. The primary purpose of the waterproof backing sheet 4 is toprevent strike-through of absorbed body fluids from the absorbent coreof the pad to the lowermost surfaces of the napkin. In one alternateembodiment of a sanitary napkin of the present invention, the waterproofbacking sheet 4 might be perforated by a series of apertures designed topermit air circulation through the lower portions of the pad to theinterior surfaces which are in contiguous association with the wearersskin. In yet another alternate embodiment of a sanitary napkin of thepresent invention, the waterproof backing sheet 4 might be eliminatedaltogether. However, in the event waterproof backing sheet 4 is eitherperforated or entirely eliminated, it would be necessary to extend topsheet lateral extensions 9, 10, 11 and 12 to overlap each other on thelower side of the napkin so as to preclude strike-through of bodyexudate from the top sheet 1, through the absorbent core layers 2 and 3,and ultimately through the bottom of the napkin.

The bottom sheet 5 is preferably formed from two superposed rectangularstrips of material having approximate dimensions of 3 in. wide by 18 in.long in one preferred embodiment of the present invention. Reemay, abasically hydrophobic, spunbonded, low basis weight, non-woven,polyester fabric having a measured weight of about 0.4 oz. per squareyard, such as is available from E. I. Du Pont De Nemours & Co., Inc.,Wilmington, Delaware, has been found to produce very satisfactoryresults in this service. Two sheets of the above described Reemay areused in a preferred embodiment to provide sufficient tensile strength.However, a single sheet of heavier Reemay or other similar materialhaving a higher degree of tensile strength might also be used for thispurpose. Other materials having equivalent porosity, weight and strengthand could also be employed to produce comparable results. Some specificexamples include: Cerex, a spunbonded, nonwoven nylon available fromMonsanto Company, St. Louis, Missouri; Typar, a spunbonded, non-wovenpolypropylene available from E. l. Du Pont De Nemours & Co., Inc.,Wilmington, Delaware; Tyvek, a spunbonded, non-woven polyethyleneavailable from E. l. Du PontDe Nemours & Co., Inc., Wilmington,Delaware; and an acrylic, resin-bonded, carded, nonwoven polyester suchas Stearns & Foster grade No. 2551 available from The Stearns & FosterCompany, Lockland, Ohio. As will be pointed out, this material is notused as an overwrap in the true sense. Its purpose is to provide acarrier means for the absorbent core layers 2 and 3, the waterproofbacking sheet 4, and the top sheet 1. The end extensions of the bottomsheet 5 provide tab material as a means of attachment to a sanitary beltsuch that the napkin is caused to assume an upwardly concaveconformation in both the longitudinal and the transverse directions,thus providing better conformance to the female anatomy in the area ofthe vulva.

Referring now to FIG. 2, the method of assembly of the componentsdepicted in FIG. 1 is more clearly illustrated. The absorbent coremember is formed by superposing the lowermost layer of absorbent corematerial 3 over the waterproof backing sheet 4, and then superposing theremaining layers of absorbent core material 2 on top of the lowermostabsorbent core layer 3 in such a manner that the rearward portions (theright end as viewed in FIG. 2) of all the absorbent core layers and thewaterproof backing sheet 4 are in vertical alignment.

The bottom sheet is prefolded upwardly by means of heat and pressurewhich tends to bond the superposed sheets together and to form lateraltabs and 16 at the leading edge of the napkin, lateral tabs 17 and 18adjacent the parallel lateral edges of absorbent core layers 2 and 3,and lateral tabs 19 and adjacent the tapered lateral edges at therearward portion of absorbent core layers 2 and 3.

In order to provide a means of attachment at the rear of a sanitarynapkin of the present invention, two slits 21 are made extending fromthe lateral edge portions of tabs 19 and 20 of the bottom sheet 5,substantially perpendicular to the longitudinal axis of the napkin.

Each slit 21 penetrates the bottom panel 22 of the bottom sheet material5 to a distance within approximately A in. to /z in. of the longitudinalaxis of the napkin. From the position of those portions of tabs 19 and20 which form the extension rearward of slits 21, as illustrated in FIG.2, one additional fold is made from each side of the said rearwardextension. Each additional fold line (designated 29 in FIG. 2) runs fromthe inwardmost edge of each lateral slit 21 to a point approximatelyone-third of the way in from the corresponding lateral edge as measuredat the rearwardmost edge of the rearward extension illustrated in FIG.2. The result of these two additional folds is a tab 24 which tapers inwidth from front to back from approximately 1 in. to /2 in. at a pointcorresponding with slits 21 to approximately /2 in. to A in. at itsrearwardmost portion, as shown in FIG. 3. Heat and pressure are appliedto bond the series of overlapping folds forming the rearward attachmenttab 24 together.

The transverse slits 21 in one preferred embodiment of the presentinvention are in vertical alignment with a point approximately /2 in. to1 /2 in. from the rearwardmost edge of the tapered segment of theabsorbent core material. Although the exact location of slits 21 is notcritical, it is preferably forward from the rearwardmost edge of theabsorbent core material, since overwrapping the juncture between thefolded rearward tab 24 and the unfolded portions of bottom panel 22 ofthe bottom sheet 5 with overlapping tabs 11 and 12 of top sheet 1impartsadditional strength to the rearward attachment tab 24.

With tabs 15, 16, 17, 18, and those portions of tabs 19 and 20 forwardof slits 21 prefolded to assume an upwardly concave or U-configurationin the transverse direction, the assemblage comprised of the waterproofbacking sheet 4, the lowermost layer of absorbent core material 3, andpreferably two layers of absorbent core material 2, is placed within thetrough-like structure formed by the bottom sheet 5 such that the leadingedges of absorbent core layers 2 are in vertical alignment with atransverse slit 14 which is made intermediate the lateral edge portionsof bottom panel 22 of the bottom sheet 5 prior to insertion of theabsorbent material.

Tabs 17 and 18 of the bottom sheet 5 are folded over the absorbent coreassemblage so as to overlap by approximately 4 in. to k in. the parallellateral edges of the uppermost layer of absorbent core material 2. Insimilar fashion, those portions of tabs 19 and 20 forward of slits 21overlap the uppermost layer of absorbent core material 2 along itsrearward lateral edges which are not parallel to each other in such amanner that tabs 19 and 20 overlap each other toward the rearwardportion of the absorbent core. This is illustrated in FIG. 2. Tabs 15and 16 at the leading edge ofthe bottom sheet 5 are folded inwardly, andheat and pressure are applied so as to bond the overlapping tabstogether to form a forward extension 27, as shown in FIGS. 3 and 4,which serves as a means of attachment to the front of a sanitary belt orholder.

The fold lines shown on the top sheet 1 in FIGS. 1 and 2 define a shapeidentical to that of the lowermost absorbent core layer 3 and thewaterproof backing sheet 4. The top sheet 1 is joined to the balance ofthe structure in such a manner that the shape defined by the fold linesis in vertical alignment with the lowermost absorbent core layer 3 andthe waterproof backing sheet 4. Tabs 9 and 10 of the top sheet 1 areadjacent the parallel lateral edges of absorbent core layers 2 and 3,while tabs 11 and 12 are adjacent the nonparallel rearward lateral edgesof absorbent core layers 2 and 3. Those portions of tabs 9, 10, 11 and12 which overlap by approximately /z in.-% in. the bottom panel 22 ofthe bottom sheet material 5 are attached to the bottom surface thereofby means of beads of glue 28, as shown in FIGS. 5 and 6. Therearwardmost tab 13 of the top sheet 1 overlaps by approximately /2in.-% in. the rearwardmost end of absorbent core layers 2 and 3 and thelowermost surface of the waterproof backing sheet 4, and is securedthereto by means of glue. Thus, the main body of the absorbent core,i.e., absorbent core layers 2 and 3, excluding the forward extension 30of the lowermost absorbent core layer 3, is secured to the bottom sheetmaterial 5.

Triangular tabs 7 and 8 and rectangular tab 6 of top sheet 1 are foldedso as to totally enclose the forwardmost extension 3a of the lowermostlayer of absorbent core material 3 and the forwardmost extension of thewaterproof backing sheet 4. Rectangular tab 6 is folded and glued to thewaterproof backing sheet 4, followed by triangular tabs 7 and 8 whichare folded and glued to both the rectangular tab 6 and those portions ofwaterproof backing sheet 4 which are exposed.

One glue which has proven satisfactory for use in assembling a sanitarynapkin of the present invention is ELVACE 1873, which is awater-resistant glue available from E. I. Du Pont De Nemours & Co.,Inc., Wilmington, Delaware. Other water resistant glues having similarproperties could also be utilized.

Addition of the top sheet 1 as described above results in a structurewhich places the top sheet in contiguous association not only with theuppermost surface of the uppermost absorbent core layer 2, but also withthe up permost surface of the forward extension 3a of the lowermostabsorbent core layer 3. Thus, absorbent core layers 2 and 3 are totallyenclosed either by top sheet 1 or waterproof backing sheet 4.

In order to impart a bias to a napkin of the present invention to assumean upwardly concave configuration in the transverse direction when worn,a longitudinally extending depression 25 of relatively narrow width ispressed into the central portion of the main body of the absorbent pad26 at the uppermost surface of the top sheet 1 (see FIG. 3). This isdone by placing a steel rod approximately 3 /2 inches long and 4 inch indiameter along the horizontal axis of the napkin, and applying a forceof approximately 4,000 lb. uniformly along the length of the rod. Thecentral depression 25 in a preferred embodiment of the present inventionis essentially co-extensive with the lateral parallel edges of absorbentcore layers 2 and 3, as illustrated in FIG.

3. However, said central depression 25 could be considerably shorterthan is illustrated in FIG. 3 or could extend nearly all the way acrossthe entire upper surface of the top sheet 1 in a longitudinal direction.

In the alternative, an interrupted central depression or a series ofdepressions parallel to the longitudinal axis of the napkin could beused to accomplish the same result. Other means may also be provided toimpart the desired bias to the napkin such that it will tend to assumean upwardly concave configuration. For example, in place of thepreferred depression 25, the upper core layer 2 may be formed such thatits longitudinal central area is of lesser thickness. In still anotherform, the same advantages may be imparted to the napkin by providing alongitudinal central slit in the core layer 3, or in both the core layer3 and the lowermost core layer 2. These and other means for providingthis function will be apparent to those skilled in the art.

FIG. 3 represents a preferred embodiment of a completely assembledsanitary napkin of the present invention prior to use. The bias toassume an upwardly concave configuration in the transverse directionprior to use due to the longitudinal central depression is clearlyillustrated in FIG. 6, which is a transverse sectional view taken alongsection line 6-6 of FIG. 3. The central depression 25 also has theeffect of densifying the absorbent core material in the immediatevicinity of the depression, thereby making the density gradient mostfavorable in the area where body fluids are most likely to be initiallydeposited.

FIG. 6 illustrates the manner in which the various components of apreferred embodiment of the instant invention are held in contiguousassociation. The absorbent core layers 2 and 3 and the waterproofbacking sheet 4 are merely stacked one upon the other. The bottom sheetmaterial 5 is provided with tabs 17 and 18 at its lateral edges at thisparticular transverse section, the outermost portions of which overlapthe uppermost surface of the uppermost layer of absorbent core material2. With the exception of a few drops of glue which may be applied tohold the bottom sheet material 5 in place while the top sheet 1 is beingadded, the overlapping portions of tabs 17 and 18 and the overlappingportions of tabs 19 and 20 forward of transverse slits 21 are held inplace merely by a sandwiching effect between the top sheet 1 and theuppermost layer of absorbent core material 2.

A sanitary napkin of the present invention exhibitsimprovements not onlyin terms of comfort to the wearer, but also in terms of the efficiencywith which the napkin is able to retain and absorb body exudate, whileat the same time preventing strike-through, and minimizing thepossibility of run-off, slippage and smearing. A sanitary napkin of thepresent invention has a width at its widest point ranging fromapproximately 2 to 3 inches, most desirably approximately 2- 4 inches.The rearward portion of such a napkin is generally tapered from themaximum width to a dimension ranging from approximately /2 to 1- /2inches, most desirable approximately 1 inch. The forward extension 23 ofthe absorbent pad of a napkin of the present invention tapers from themaximum width to a dimension ranging between V2 and l-& inches, mostdesirably approximately 1 inch. The overall length of the napkin alongits longitudinal axis, exclusive of its attachment tabs, typicallyranges between approximately 6-/2 and 8- /6 inches, most desirablyapproximately 7-% inches.

The longitudinal distance over which the rearward taper of the absorbentpad 26 occurs ranges between approximately 3 and 4 inches, mostdesirably approximately 3-/2 inches. The longitudinal distance overwhich the forward taper of the forward extension 23 of the absorbent padoccurs is in the range of approximately /2 to l-% inches, most desirablyapproximately 1 inch. The forward attachment tab 27 typically rangesbetween approximately 3- /2 and 5- /2 inches in length, most desirablyabout 4- /2 inches as measured from the leading edge of the main body ofthe absorbent pad 26, i.e., that portion of the absorbent pad notincluding the forwardmost extension 23 thereof. The rearward attachmenttab 24 typically ranges between approximately 5- /2 and 7- /2 inches inlength, most desirably about 6- /2 inches as measured from therearwardmost edge of the main body of the absorbent pad 26.

It is recognized that although only one preferred embodiment of thepresent invention has been described above, a sanitary napkin having anelliptical or any other equivalent configuration of the same generalproportions as those listed above could be utilized to effect a similarresult.

It will be noted from FIG. 4 that a napkin of the present invention isintended to be worn with its wider portion toward the front of the body,with the forwardmost extension 23, which is free to bend relative to themain body of the absorbent pad, to a considerably higher elevation thanthe main body of the absorbent pad 26.

A sanitary napkin of the present invention has been found to have betterconformation to the female anatomy. Its tapered rearward portion issufficiently narrow to avoid bunching in the anal area, while itsmaximum width is such that the lateral edge portions of the absorbentpad contact the null point of the groin line, i.e., where there isvirtually no movement of the thighs relative to the trunk of the body.Each lateral edge portion of the absorbent pad is accommodated in avault formed by the juncture of each thigh and the adjacent labiummajora, such that relative motion between the inner portions of thethigh and each lateral edge portion of the absorbent pad is essentiallynon-existent. This is best illustrated in FIG. 5, which is an enlargedtransverse sectional view of such a napkin when placed in use. Thus, thesize and shape of a sanitary napkin of the present invention acting inconjunction with the other structural features of the present inventioneliminate the downwardly concave or inverted U transverse configurationwhich is normally assumed by prior art rectangular style sanitarynapkins, thereby minimizing the possibility of run-off of body exudate.

It should be noted that the overall reduction in size of the absorbentpad of a sanitary napkin of the present invention, particularly towardits rearward portion, would not be practical without the unique abilityof the top sheet 1 and absorbent core layers 2 and 3 of the presentinvention to rapidly transmit and absorb body exudate much moreeffectively than is possible with conventional overwrap and corematerials due to the favorable density gradient existing between the topsheet 1 and the absorbent core layers 2 and 3. The favorable densitygradient in turn provides a diminishing capillary size gradient and afavorable liquid contact angle gradient, both of which exist regardlessof whether the absorbent core material is in a moist or a dry state.

In the present invention, stress on the central portion of the main bodyof the absorbent pad 26 is relieved by means of a transverse slit 14 orother similar interruption in the bottom sheet material 5. Thetransverse discontinuity or slit 14 in the bottom sheet material islocated in bottom panel 22 intermediate the lateral edges of the forwardattaching tab 27, which is shown in FIGS. 3 and 4. The transverseinterruption or slit 14 is preferably in vertical alignment with theleading edge of absorbent core layers 2, Le, with the leading edge ofthe main body of the absorbent pad 26. The slit 14 may also be as muchas 1 inch from the aforesaid vertical alignment to achieve the objectsof the invention. The transverse interruption or slit 14 functions totransmit stress imposed by tension on the attachment tabs 27 and 24,during wearing, to the lateral edges of the absorbent pad 26. Selectiveplacement of the tensional stress at the lateral edges of the absorbentpad tends to form the absorbent pad 26 into a cupped receptacle for thecollection of body exudate, since, as shown in FIG. 5, the lateral edgesof the core are held snugly against the body in the vaults formed by thejuncture of each thigh and the adjacent labium majora, while the centralportion of the absorbent pad 26 along the longitudinal axis is free tomove downwardly, thereby bridging the labia majora. The longitudinaldepression 25 illustrated in FIGS. 3, 5 and 6 imparts a bias to theabsorbent pad 26 which, when coupled with the forces induced by the tabs27 and 24, tends to cause the longitudinal axis of the absorbent pad tomove downwardly. Thus, the cupping of the absorbent pad 26 is causedprincipally by the addition of the slit 14 (which causes selectiveapplication of stress from tabs 27 and 24) and is abetted by thedepression 25.

The present invention also discloses a sanitary napkin construction inwhich a forward extension 23 of the absorbent pad 26 is formed from theforwardmost extension 3a of the lowermost layer of absorbent corematerial 3, the forwardmost extension of the waterproof backing sheet 4,and the forwardmost extension of the top sheet 1 which totally enclosesthe forwardmost extension 3a of the lowermost absorbent core layer 3 andthe forwardmost extension of the waterproof backing sheet 4 by means ofoverlapping rectangular tab 6 and overlapping triangular tabs 7 and 8.The forward extension of the absorbent pad thus formed is free to bendrelative to the main body ofthe absorbent pad 26 along a linecorresponding with the leading edge of absorbent core layers 2. This isdue to the fact that the forward extension 23 is not in any way confinedby tabs 17 and 18 of the bottom sheet material 5, as is the main body ofthe absorbent pad 26. In addition, since the forward extension 23 iscomprised of only one layer of absorbent core material 3, the waterproofbacking sheet 4, and the top sheet 1, very little effort is required tobend the forward extension 23 relative to the main body of the absorbentpad 26. The ability of the forward extension 23 to bend with easerelative to the main body of the absorbent pad 26 provides both improvedfit and comfort, since it causes the absorbent pad to assume an upwardlyconcave or U-shape in the'longitudinal direction with the application ofrelatively small tensional forces.

The forward extension 23 also provides a capacity advantage when worn,since it forms a dam to restrain the flow of body exudate over the frontof the napkin. In addition, because of the compliant nature of the topsheet 1 and the fact that the forward extension 23 has less bulk thanthe main body of the absorbent pad 26, it is more pliable and tends toconform to the female body with relative ease, thereby minimizing theformation of any ridges or troughs along its lateral edges. Eliminationof ridges and troughs along the lateral edges of a sanitary napkin isdesirable because their presence tends to promote the flow of bodyexudate toward the lateral edges of the napkin, and hence increases thepossibility of run-off and consequent soiling of undergarments.

The front dam formed by the forward extension 23, cooperates when wornwith the transverse interruption or slit 14 in the bottom sheet material5 and the longitudinal depression 25 such that while the lateral edgesof the main body of the absorbent pad 26 are held snugly against thebody due to the tensional forces induced in the lateral edge portions ofthe absorbent pad as a result of the slit, the forward extension 23conforms easily and hence forms a snug fit against the frontal portionsof the body, while the central depression 25 causes the central portionof the main body of the absorbent pad 26 to move downwardly to bridgethe labia majora and form a receptacle for the collection of menses orother body exudate. Menses or other body exudate cannot readily escapetoward the rearward portion of the absorbent pad 26 due to the fact thatits rearwardmost edge is so narrow that the tensional forces along thelateral edges of the main body of the absorbent pad intersect at itsrearwardmost portion, thereby forming a sealagainst the body rearward ofthe vulva.

Thus a triangular shaped dam is formed about the periphery of the vulva,while the central portion of the napkin is encouraged to movedownwardly, thus allowing it to form a totally enclosed receptacle forthe collection of menses or other body exudate. Fluid deposited on thetop sheet 1 is retained within the totally enclosed receptacle so formeduntil it can be transmitted from the topsheet 1 into the absorbent corelayers 2 and 3. Run-off of menses or other body exudate due toexceptionally heavy flow is thereby minimized in any given direction.

Therefore, although a sanitary napkin of the present invention is morecomfortable to the wearer due to its reduced size, its revised shape andits upwardly concave conformation in both the longitudinal and thetransverse directions to better fit the female anatomy, it is alsoconsiderably more effective in retaining and absorbing menses or otherbody exudate than a sanitary napkin of conventional rectangular designhaving considerably more surface area and absorbent core materialpresent. It is also more effective and more comfortable than sanitarynapkins of the prior art having tapered segments at their rearwardportion, due to the unique interaction of the transverse slit 14 in thebottom sheet material 5, the central longitudinal depression 25 in themain body of the absorbent pad 26, and the forward extension of theabsorbent pad 23 which cause the napkin to assume an upwardly concaveconformation in the area of the labia majora, thereby minimizing contactbetween the top sheet 1 and the wearers skin, and at the same timeminimizing the formation of ridges and troughs which are usually formedalong the lateral edges of a flat sanitary napkin when it is attached toa sanitary belt or holder.

As has been mentioned earlier in this specification, the overallreduction in size of the absorbent pad of a sanitary napkin of thepresent invention to better fit the female anatomy would not bepractical unless the core material were more effectively utilized toabsorb menses or other body exudate than is the case with prior artsanitary napkins. In sanitary napkin construction it is generallydesirable for the absorbent structure to immediately accept bodyexudate, rapidly transport the exudate away from the discharge sourceand effectively contain the exudate within the confines of the napkin,while the top surface of the napkin is maintained relatively dry. Inaddition, the absorbed exudate should not be allowed to spread to thesides of the napkin, run over the top edges of the napkin, or soakthrough the bottom of the napkin, and this is especially true where theabsorptive capacity of the napkin has not been fully utilized.

As illustrated in FIGS. 1, 2, and 6, a preferred embodiment of thepresent invention consists of three layers of absorbent core material,compressed airfelt in this instance, the lowermost layer of which has atrapezoidal forward extension. The airfelt is densified by drycompression and may be subjected to any one of a number of processesdesigned to provide acceptable lateral softness in the finished product,e.g., mechanical micro-creping carried out between differentially loadedrubber belts and/or a differentially loaded rubber belt and a hardsurface. Dry compression increases the airfelts density by reducing itsphysical thickness, while any one of the softening processes can be usedto impart softness and compliance which would not otherwise result ifonly dry compression were utilized. The stiffness or flexural rigidityof a specimen of compressed airfelt such as is utilized in a preferredembodiment of the present invention having an overall width of 3.81 cm.1.50 in.) and an overall length of 6.99 cm. (2.75 in.) can be measuredby means of a Taber V-5 Stiffness Tester, Model 150 B, as manufacturedby the Taber Instrument Corporation of North Tonawanda, New York. Aprocedure identical to that utilized to measure the stiffness orflexural rigidity of paperboard may be utilized. The procedure involvesdetermining the required bending moment in gram-centimeters to deflectthe free end of a 3.81 cm. (1.50 in.) wide vertically clamped specimenas described above l5from its center line when the load is applied 5 cm.away from the clamp. Compressed airfelt such as is used in a preferredembodiment of the present invention having a caliper of between 0.127and 0.152 cm. (0.05 and 0.06 in.) which has been subjected to any of thesoftening processes well known in the art typically exhibits a softnessrange between about 1.2 and 8.7 gramcentimeters, whereas compressedairfelt of equivalent caliper which has not been subjected to any typeof softening process typically exhibits a softness range between and 18gram-centimeters. It is to be understood that various thicknesses ofcompressed airfelt could be utilized in the present invention. However,the Taber softness range would differ for different thicknesses ofmaterial and, therefore, the preferred Taber softness range would haveto be individually determined for any given thickness of material.

In a sanitary napkin of the present invention having a total weight ofapproximately 10 to 12 gm., the total weight ofthe absorbent corematerial is typically in the range of approximately 7 to 8 gm. Apreferred embodiment of the present invention has the machine directionof the compressed airfelt aligned transverse to the longitudinal axis ofthe napkin. However, there does not appear to be a discernibledifference in the characteristics of the finished product when themachine direction of the airfelt is aligned parallel to the longitudinalaxis of the napkin.

If desired, a resin spray (e.g., Rohm and Haas HA-8) or other bondingagent may be applied to the exterior surfaces of absorbent layers 2 and3 while they are still at low density, i.e., prior to compression, toreduce the tendency of the airfelt to shred and tear when dry and ballup and rope when wet and to improve the surface dryness. However, sincea sanitary napkin of the present invention experiences virtually norelative movement with respect to itself or with respect to the trunk ofthe body or the inner portions of the thighs, this is not essential tothe practice of the invention.

Such a strength imparting treatment would be of greatest benefit inabsorbent bandages which experience considerable internal movement andshifting, such as disposable diapers, etc. Bonding of the exteriorsurfaces of the absorbent core members to impart both tensile andcohesive strength could be carried out to impart wet strength to theairfelt by bonding the surface fibers together at contact points.

In a preferred embodiment of the present invention, the top sheet 1 isin contiguous association with the uppermost surface of the uppermostlayer of absorbent core material 2 and the uppermost surface of theforward extension 3a of absorbent core layer 3. All the absorbent corelayers are in contiguous association with each other, while thelowermost surface of the lowermost absorbent core layer 3 is incontiguous association with the waterproof backing sheet 4. Due to thehydrophobic nature and the low density of the top sheet 1 in a preferredembodiment of the present invention, fluid deposited on the top sheetmigrates rapidly towards the more dense absorbent core layers 2 and 3which are basically hydrophilic, rather than spreading laterally acrossthe surface of the top sheet 1. The rapid transmission of fluid causedby capillary attraction keeps the top sheet feeling dry, and, therefore,more comfortable to the wearer. When the uppermost absorbent core layer2 makes contact with the fluid, it begins to absorb the fluid and itslattice structure begins to expand, particularly in the area of thelongitudinal depression 25. As the pore size in the wetted portion ofthe absorbent core increases, it creates a favorable density gradientbetween the moist and dry segments of absorbent core layers 2 and 3.Thus fluid is rapidly transmitted not only from one layer to the next,but also toward the lateral edges of each layer of absorbent corematerial. Because the density of the top sheet 1 remains basicallyunchanged due to its hydrophobic nature, its pore size remains largerthan the pore size of even the moist layers of absorbent core material 2and 3. Therefore, fluid which has been absorbed by absorbent core layers2 and 3 does not tend to migrate back towards the top sheet 1. Since theabsorbent core layers 2 and 3 are covered on their uppermost and lateraledge portions by the basically hydrophobic top sheet 1, and since theextensions of the hydrophobic top sheet 1 are bonded to the lowermostside of either the bottom sheet material 5 or the waterproof backingsheet 4, absorbed fluid is trapped within a capsule-like member formedby the top sheet I and the waterproof backing sheet 4. Thus, the topsheet 1 acts as a unidirectional flow member which permits the flow offluid only towards the absorbent core layers 2 and 3 and not in thereverse direction. In addition, since a sanitary napkin of the presentinvention is not subjected to compressional forces by the inner portionsof the thighs of the wearer, there is virtually no tendency to forceabsorbed fluids from the absorbent core layers 2 and 3 to the top sheet1 due to the application of pressure. This tends to promote longerwearing times, since the top surface of the pad feels drier and has aless objectionable appearance. Longer wearing times in turn permit moreeffective utilization of the absorptive capacity of absorbent corelayers 2 and 3. The waterproof backing sheet 4, meanwhile, gives theuser confidence to wear the pad for longer periods of time since she isprotected against strike-through.

Many modifications of the above invention may be used and it is notintended to hereby limit to the particular embodiments shown ordescribed. The terms used in describing the invention are used in theirdescriptive sense and not as terms of limitation, it being intended thatall equivalents thereof be included within the scope of the appendedclaims.

What is claimed is:

1. An absorbent bandage, comprising:

a. a hydrophilic absorbent core of compressed absorbent material havinga density throughout of from about 0.15 to about 0.30 gm. per cubiccentimeter as measured under a load of 50 gm. per square inch, 21 0.050.06 in. thick by 1.50 in. wide specimen of said absorbent core materialhaving a Taber softness between about 1.2 and about 8.7 gramcentimeters;

b. a hydrophobic topsheet having a density substantially less than thatof said absorbent core secured in superposed relation to said absorbentcore, said absorbent core and said topsheet comprising an absorbent padfor rapidly absorbing and retaining body exudate; and a bottom sheetunderlying and secured to said absorbent pad for supporting saidabsorbent pad inuse.

2. The absorbent bandage of claim 1, including a thin, flexiblebacksheet of waterproof material underlying and co-extensive with saidabsorbent core and located intermediate with said absorbent core andsaid bottom sheet, said waterproof backsheet thereby preventingstrike-through of body exudate absorbed by said absorbent core to thelowermost surface of said bandage.

3. The absorbent bandage of claim 1, wherein the lowermost surface ofsaid hydrophilic absorbent core is completely overwrapped by theoverlapping portions of said hydrophobic topsheet, thereby preventingstrikethrough of body exudate absorbed by said sbsorbent core to thelowermost surface of said bandage.

4. The absorbent bandage of claim 1, wherein said hydrophilic absorbentcore is comprised of compressed airfelt.

5. The absorbent bandage of claim 4, wherein the exterior surfaces ofthe airfelt have been treated with a wet-strengthening agent prior toinitial compression to bond the surface fibers of the airfelt togetherat contact points.

6. The absorbent bandage of claim 1, wherein said hydrophobic topsheetis comprised of non-woven, needle-punched polyester fabric having adensity of from about 0.03 to about 0.13 gm. per cubic centimeter asmeasured under a load of 50 gm. per square inch.

7. The absorbent bandage of claim 1, wherein said bottom sheet iscomprised of hydrophobic, spunbonded, low basis weight, non-wovenpolyester fabric.

8. An absorbent bandage suitable for use as a catamenial or anincontinent device, comprising:

a. an absorbent pad having reduced overall width toward its rearwardmostportion;

b. a bottom sheet underlying and secured to said absorbent pad, saidbottom sheet having forward and rearward extensions projectingsubstantially beyond said absorbent pad for supporting said absorbentpad in-use;

c. longitudinally extending means in said absorbent pad for imparting anupwardly concave bias to said absorbent pad in the transverse direction;and

d. a discontinuity in the forward extension of said bottom sheetproximate to the forward edge of said absorbent pad and transverselyoriented to the longitudinal axis of said absorbent bandage toconcentrate normal in-use tensile forces applied to said forward andrearward bottom sheet extensions along the lateral edge portions of saidabsorbent pad, said concentration of tensile forces in cooperation withthe reduced overall width of the rearwardmost portion of said absorbentpad and the aforesaid longitudinally extending means for imparting biascausing said absorbent pad to assume an upwardly concave conformation inboth the longitudinal and the transverse directions to prevent run-offand smearing of body exudate deposited on the uppermost surface of saidbandage.

9. The absorbent bandage of claim 8, wherein said longitudinallyextending means for imparting an upwardly concave bias to said absorbentpad is comprised of a longitudinally extending depression of relativelynarrow width, said depression being centrally-located in the uppermostsurface of said absorbent pad.

10. The absorbent bandage of claim 8, wherein said discontinuity in theforward extension of said bottom sheet is comprised of a slit locatedintermediate the lateral edge portions of said forward extension, saidslit being transversely oriented to the longitudinal axis of saidabsorbent bandage.

11. An absorbent bandage suitable for use as a catamenial or anincontinent device, comprising:

a an absorbent pad having reduced overall width toward its rearwardmostportion, said absorbent pad being comprised of a hydrophilic absorbentcore of compressed absorbent material having a density of from about0.15 to about 0.30 grams per cubic centimeter as measured under a loadof 50 gm. per square inch, a 0.05 0.06 in. thick by 1.50 in. widespecimen of said absorbent core material having a Taber softness betweenabout 1.2 and about 8.7 gram-centimeters, and a hydrophobic topsheetsecured in superposed relation to said absorbent core, said topsheethaving a density of from about 0.03 to about 0.13 gm. per cubiccentimeter as measured under a load of 50 gm. per square inch;

b. a bottom sheet underlying and secured to said absorbent pad, saidbottom sheet having forward and rearward extensions projectingsubstantially beyond said absorbent pad for supporting said absorbentpad in-use;

c. longitudinally extending means in said absorbent pad for imparting anupwardly concave bias to said absorbent pad in the transverse direction;and

d. a discontinuity in the forward extension of said bottom sheetproximate to the forward edge of said absorbent pad, whereby normalin-use tension on said forward and rearward bottom sheet extensions incooperation with the reduced overall width of the rearwardmost portionof said absorbent pad and the aforesaid longitudinally extending meansfor imparting bias causes said absorbent pad to assume an upwardlyconcave conformation in both the longitudinal and the transversedirections to prevent run-off and smearing of body exudate deposited onthe uppermost surface of said bandage.

12. The absorbent bandage of claim 11, wherein said longitudinallyextending means for imparting an upwardly concave bias to said absorbentpad is comprised of a centrally-located, longitudinally extending slitin the lowermost surface of said absorbent core.

13. An absorbent bandage suitable for use as a catamenial or anincontinent device, comprising an absorbent pad having a main bodyportion and a forward extension, said forward extension being of lesserbulk than said main body portion, and a bottom sheet having forward andrearward extensions projecting substantially beyond said absorbent padunderlying and secured to said main body portion but not to said forwardextension, the forward extension of said absorbent pad being free tobend relative to said bottom sheet and to the main body portion of saidabsorbent pad, whereby normal in-use tension on said forward andrearward bottom sheet extensions causes the forward extension of saidabsorbent pad to bend upwardly relative to the main body portion toprovide a dam for restraining excessive forward flow of body exudate.

14. An absorbent bandage suitable for use as a catamenial or anincontinent device, comprising an absorbent pad having a main bodyportion and a forward extension, the main body portion of said absorbentpad having reduced overall width toward its rearwardmost end, and abottom sheet having forward and rearward extensions projectingsubstantially beyond said absorbent pad underlying and secured to saidmain body portion, the forward extension of said absorbent pad beingfree to bend relative to said bottom sheet and to the main body portionof said absorbent pad, whereby normal in-use tension on said forward andrearward bottom sheet extensions causes the forward extension of saidabsorbent pad to bend upwardly relative to the main body portion toprovide a dam for restraining excessive forward flow of body exudate,said absorbent bandage including longitudinally extending means in saidabsorbent pad for imparting an upwardly concave bias to said absorbentpad in the transverse direction, and a transversely orienteddiscontinuity in the forward extension of said bottom sheet proximate tothe forward edge of the main body portion of said absorbent pad, wherebynormal in-use tension on said forward and rearward bottom sheetextensions in cooperation with the reduced overall width toward therearwardmost end of said absorbent pad and the aforesaid longitudinallyextending means for imparting bias causes said absorbent pad to assumean upwardly concave conformation in both the longitudinal and thetransverse directions, thereby forming, in cooperation with the forwardextension of said absorbent pad, a closesided, cupped receptacle aboutthe vulva for the collection and retention of body exudate.

15. The absorbent bandage of claim 14, wherein said absorbent pad has amaximum width of between about 2 inches and about 3 inches, said widthtapering to between about /2 inch and about 1 inch at the rearwardmostend of the main body portion of said absorbent pad and to between about/2 inch and about 1- /2 inches at the forwardmost end of the forwardextension of said absorbent pad, said absorbent pad having an overalllength, including said forward extension, of between about 6- /2 inchesand about 8- /2 inches.

16. The absorbent bandage of claim 14, wherein said absorbent pad iscomprised of a hydrophilic absorbent core layer of compressed absorbentmaterial having a density throughout of from about 0.22 to about 0.26gm. per cubic centimeter as measured under a load of 50 gm. per squareinch, a 0.05 0.06 in. thick by 1.50 in. wide specimen of said absorbentcore material having a Taber softness between about 1.2 and about 8.7gram-centimeters, and a hydrophobic topsheet secured in superposedrelation to said absorbent core layer, said topsheet having a density offrom about 0.03 to about 0.08 gm. per cubic centimeter as measured undera load of 50 gm. per square inch, said absorbent core layer and saidtopsheet comprising both the main body portion and the forward extensionof said absorbent pad.

17. The absorbent bandage of claim 16, including a thin, flexiblebacksheet of waterproof material underlying and coextensive with saidabsorbent core layer, said backsheet being located intermediate saidabsorbent core layer and said bottom sheet in the area ofthe main bodyportion of said absorbent pad and intermediate said absorbent core layerand the overlapping portions of said topsheet in the area of the forwardextension of said absorbent pad, said waterproof backsheet therebypreventing strike-through of body exudate absorbed by said absorbentcore layer to the lowermost surface of said bandage.

18. The absorbent bandage of claim 16, wherein said hydrophilicabsorbent core layer is comprised of compressed airfelt, saidhydrophobic topsheet is comprised of non-woven, needle-punched polyesterfabric, and said bottom sheet is comprised of hydrophobic, spunbonded,low basis weight, non-woven, polyester fabric. =l

UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTIONPATENT N0. 3,871,378

DATED 1 March 18, 1975 |NV ENTOR(S) Robert C. Duncan, Grace L. Smith Itis certified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below: U

ABSTRACT, line 12, "two" should read top Column 8, line 33, after"weight and strength" delete "and".

. Claim 2 Column 17 line 46 after "intermediate" delete "with" Signedand Scaled this Seventh Day of December 1976 [SEAL] Anesr:

RUTH C. MASON C. MARSHALL DANN A [resting Officer, Commissioneroj'larenrs and Trademarks

1. An absorbent bandage, comprising: a. a hydrophilic absorbent core ofcompressed absorbent material having a density throughout of from about0.15 to about 0.30 gm. per cubic centimeter as measured under a load of50 gm. per square inch, a 0.05 - 0.06 in. thick by 1.50 in. widespecimen of said absorbent core material having a Taber softness betweenabout 1.2 and about 8.7 gram-centimeters; b. a hydrophobic topsheethaving a density substantially less than that of said absorbent coresecured in superposed relation to said absorbent core, said absorbentcore and said topsheet comprising an absorbent pad for rapidly absorbingand retaining body exudate; and c. a bottom sheet underlying and securedto said absorbent pad for supporting said absorbent pad in-use.
 2. Theabsorbent bandage of claim 1, including a thin, flexible backsheet ofwaterproof material underlying and co-extensive with said absorbent coreand located intermediate with said absorbent core and said bottom sheet,said waterproof backsheet thereby preventing strike-through of bodyexudate absorbed by said absorbent core to the lowermost surface of saidbandage.
 3. The absorbent bandage of claim 1, wherein the lowermostsurface of said hydrophilic absorbent core is completely overwrapped bythe overlapping portions of said hydrophobic topsheet, therebypreventing strike-through of body exudate absorbed by said sbsorbentcore to the lowermost surface of said bandage.
 4. The absorbent bandageof claim 1, wherein said hydrophilic absorbent core is comprised ofcompressed airfelt.
 5. The absorbent bandage of claim 4, wherein theexterior surfaces of the airfelt have been treated with awet-strengthening agent prior to initial compression to bond the surfacefibers of the airfelt together at contact points.
 6. The absorbentbandage of claim 1, wherein said hydrophobic topsheet is comprised ofnon-woven, needle-punched polyester fabric having a density of fromabout 0.03 to about 0.13 gm. per cubic centimeter as measured under aload of 50 gm. per square inch.
 7. The absorbent bandage of claim 1,wherein said bottom sheet is comprised of hydrophobic, spunbonded, lowbasis weight, non-woven polyester fabric.
 8. An absorbent bandagesuitable for use as a catamenial or an incontinent device, comprising:a. an absorbent pad having reduced overall width toward its rearwardmostportion; b. a bottom sheet underlying and secured to said absorbent pad,said bottom sheet having forward and rearward extensions projectingsubstantially beyond said absorbent pad for supporting said absorbentpad in-use; c. longitudinally extending means in said absorbent pad forimparting an upwardly concave bias to said absorbent pad in thetransverse direction; and d. a discontinuity in the forward extension ofsaid bottom sheet proximate to the forward edge of said absorbent padand transversely oriented to the longitudinal axis of said absorbentbandage to concentrate normal in-use tensile forces applied to saidforward and rearward bottom sheet extensions along the lateral edgeportions of said absorbent pad, said concentration of tensile forces incooperation with the reduced overall width of the rearwardmost portionof said absorbent pad and the aforesaid longitudinally extending meansfor imparting bias causing said absorbent pad to assume an upwardlyconcave conformation in both the longitudinal and the transversedirections to prevent run-off and smearing of body exudate deposited onthe uppermost surface of said bandage.
 9. The absorbent bandage of claim8, wherein said longitudinally extending means for imparting an upwardlyconcave biAs to said absorbent pad is comprised of a longitudinallyextending depression of relatively narrow width, said depression beingcentrally-located in the uppermost surface of said absorbent pad. 10.The absorbent bandage of claim 8, wherein said discontinuity in theforward extension of said bottom sheet is comprised of a slit locatedintermediate the lateral edge portions of said forward extension, saidslit being transversely oriented to the longitudinal axis of saidabsorbent bandage.
 11. An absorbent bandage suitable for use as acatamenial or an incontinent device, comprising: a an absorbent padhaving reduced overall width toward its rearwardmost portion, saidabsorbent pad being comprised of a hydrophilic absorbent core ofcompressed absorbent material having a density of from about 0.15 toabout 0.30 grams per cubic centimeter as measured under a load of 50 gm.per square inch, a 0.05 - 0.06 in. thick by 1.50 in. wide specimen ofsaid absorbent core material having a Taber softness between about 1.2and about 8.7 gram-centimeters, and a hydrophobic topsheet secured insuperposed relation to said absorbent core, said topsheet having adensity of from about 0.03 to about 0.13 gm. per cubic centimeter asmeasured under a load of 50 gm. per square inch; b. a bottom sheetunderlying and secured to said absorbent pad, said bottom sheet havingforward and rearward extensions projecting substantially beyond saidabsorbent pad for supporting said absorbent pad in-use; c.longitudinally extending means in said absorbent pad for imparting anupwardly concave bias to said absorbent pad in the transverse direction;and d. a discontinuity in the forward extension of said bottom sheetproximate to the forward edge of said absorbent pad, whereby normalin-use tension on said forward and rearward bottom sheet extensions incooperation with the reduced overall width of the rearwardmost portionof said absorbent pad and the aforesaid longitudinally extending meansfor imparting bias causes said absorbent pad to assume an upwardlyconcave conformation in both the longitudinal and the transversedirections to prevent run-off and smearing of body exudate deposited onthe uppermost surface of said bandage.
 12. The absorbent bandage ofclaim 11, wherein said longitudinally extending means for imparting anupwardly concave bias to said absorbent pad is comprised of acentrally-located, longitudinally extending slit in the lowermostsurface of said absorbent core.
 13. An absorbent bandage suitable foruse as a catamenial or an incontinent device, comprising an absorbentpad having a main body portion and a forward extension, said forwardextension being of lesser bulk than said main body portion, and a bottomsheet having forward and rearward extensions projecting substantiallybeyond said absorbent pad underlying and secured to said main bodyportion but not to said forward extension, the forward extension of saidabsorbent pad being free to bend relative to said bottom sheet and tothe main body portion of said absorbent pad, whereby normal in-usetension on said forwardand forward and bottom sheet extensions causesthe forward extension of said absorbent pad to bend upwardly relative tothe main body portion to provide a dam for restraining excessive forwardflow of body exudate.
 14. And absorbent bandage suitable for use as acatamenial or an incontinent device, comprising an absorbent pad havinga main body portion and a forward extension, the main body portion ofsaid absorbent pad having reduced overall width toward its rearwardmostend, and a bottom sheet having forward and rearward extensionsprojecting substantially beyond said absorbent pad underlying andsecured to said main body portion, the forward extension of saidabsorbent pad being free to bend relative to said bottom sheet and tothe main body portion of said absorbent pad, whereby normal in-usetension on said forward and Rearward bottom sheet extensions causes theforward extension of said absorbent pad to bend upwardly relative to themain body portion to provide a dam for restraining excessive forwardflow of body exudate, said absorbent bandage including longitudinallyextending means in said absorbent pad for imparting an upwardly concavebias to said absorbent pad in the transverse direction, and atransversely oriented discontinuity in the forward extension of saidbottom sheet proximate to the forward edge of the main body portion ofsaid absorbent pad, whereby normal in-use tension on said forward andrearward bottom sheet extensions in cooperation with the reduced overallwidth toward the rearwardmost end of said absorbent pad and theaforesaid longitudinally extending means for imparting bias causes saidabsorbent pad to assume an upwardly concave conformation in both thelongitudinal and the transverse directions, thereby forming, incooperation with the forward extension of said absorbent pad, aclose-sided, cupped receptacle about the vulva for the collection andretention of body exudate.
 15. The absorbent bandage of claim 14,wherein said absorbent pad has a maximum width of between about 2 inchesand about 3 inches, said width tapering to between about 1/2 inch andabout 1 inch at the rearwardmost end of the main body portion of saidabsorbent pad and to between about 1/2 inch and about 1- 1/2 inches atthe forwardmost end of the forward extension of said absorbent pad, saidabsorbent pad having an overall length, including said forwardextension, of between about 6- 1/2 inches and about 8- 1/2 inches. 16.The absorbent bandage of claim 14, wherein said absorbent pad iscomprised of a hydrophilic absorbent core layer of compressed absorbentmaterial having a density throughout of from about 0.22 to about 0.26gm. per cubic centimeter as measured under a load of 50 gm. per squareinch, a 0.05 - 0.06 in. thick by 1.50 in. wide specimen of saidabsorbent core material having a Taber softness between about 1.2 andabout 8.7 gram-centimeters, and a hydrophobic topsheet secured insuperposed relation to said absorbent core layer, said topsheet having adensity of from about 0.03 to about 0.08 gm. per cubic centimeter asmeasured under a load of 50 gm. per square inch, said absorbent corelayer and said topsheet comprising both the main body portion and theforward extension of said absorbent pad.
 17. The absorbent bandage ofclaim 16, including a thin, flexible backsheet of waterproof materialunderlying and coextensive with said absorbent core layer, saidbacksheet being located intermediate said absorbent core layer and saidbottom sheet in the area of the main body portion of said absorbent padand intermediate said absorbent core layer and the overlapping portionsof said topsheet in the area of the forward extension of said absorbentpad, said waterproof backsheet thereby preventing strike-through of bodyexudate absorbed by said absorbent core layer to the lowermost surfaceof said bandage.
 18. The absorbent bandage of claim 16, wherein saidhydrophilic absorbent core layer is comprised of compressed airfelt,said hydrophobic topsheet is comprised of non-woven, needle-punchedpolyester fabric, and said bottom sheet is comprised of hydrophobic,spunbonded, low basis weight, non-woven, polyester fabric.